In a plasma process that is performed for the fabrication of a semiconductor device, or a liquid crystal display device, a processing gas is introduced into an airtight processing container having electrodes provided therein. Radio frequency power is then applied to the electrodes so as to change the processing gas to plasma. In this manner a predetermined process, such as etching of a surface of an object to be processed or deposition of a layer on the surface of the object, is performed.
However, with diversification of the fabrication process, the need may occur in some cases for performing the predetermined process under a condition in which the radio frequency power applied to the electrodes is low. Moreover, in the case where the plasma processing apparatus is continuously operated for a long time—for example, during fabrication of a product—foreign particles generated by the process may adhere to the inside of the plasma processing apparatus, thus preventing stable generation of plasma.
The present invention was made in view of the aforementioned problems of the conventional plasma processing method. Therefore, it is an object of the present invention to provide a novel and improved plasma processing method that can stably generate plasma, even in the case where the applied radio frequency power is low and even after plasma processing apparatus is operated for a long time.